The use of heterogeneous catalysts over homogeneous catalysts has several advantages such as allowing the use of fixed beds, ease of separation of catalyst from the product and catalyst recovery and regeneration.
Traditionally, to produce heterogeneous catalysts from metals of the transition element series, these metals have been deposited on inert supports such as alumina or silica. More recently metal catalysts have been covalently attached to inert resin backbones by use of diphenylphosphine or other ligands which are attached directly to the polymer and coordinately bonded to the metal. Typical examples of this type are found in U.S. Pat. No. 3,998,864, issued Dec. 21, 1976, and in Pittman et al, Chemtech, p. 560-566, 1973.
In the composition of the invention, on the other hand, the metal is coordinately bound to a ligand and the ligand is ionically bound to an ion exchange resin. Some of the advantages of the materials of the invention are that the materials are relatively simple to prepare using commercially available compounds, the preparations involve no exotic conditions, and often times may be carried out in an aqueous solvent system and the resins may be easily stripped of metal and ligands for isolation of the metal species and regeneration of the catalyst. The resin based catalysts of this invention have unique selectivity-reactivity properties when compared to their homogeneous analogues.